Transmission electron microscopes (TEM) and scanning transmission electron microscopes (STEMs) are configured for observation of a sample in vacuum atmosphere. Recently there is a growing need for analysis of the structure or characteristics of a substance or for in situ observation of a synthetic process of a substance in special atmosphere such as gas or liquid. To this end, observation of a sample in special atmosphere with an electron microscope is required.
Patent Literatures 1 and 2 describe a sample holder for observation of a sample in gas atmosphere with an electron microscope. This sample holder has a mechanism that holds a sample between two grids, introduces gas therebetween and then exhausts the gas. This sample holder, however, is not configured for observation the sample at a specific site thereof as well as prevention of contamination of a diaphragm by irradiation with electron beams.
Patent Literature 3 describes a microreactor for observation of a sample in specific atmosphere with an electron microscope. This microreactor is configured to supply gas or liquid to a chamber formed between two cover layers that are partially transparent. The microreactor further is equipped with a mechanism that heats the cover layers as well as fluid or a sample in the chamber. A heating element is placed in or on the cover layer, and the sample is placed on the heating element.